Problem with the sketch is that one has to be very careful what combination of options one enables. The actual problem turns out to have been that the compiled download was too big. The error message wasn't very helpful, but I did eventually find the comment in your online documentation that it won't all fit in an Arduino with a 328.

I guess that this error message should come back with something like - transferred sketch too large.

Got it functioning. now need to add a few transistors and get the sidetone and a key output functioning.

Built a quick and dirty shield so I can also use my Uno for other things. May build one using just the bare Arduino chip and a scrap of circuit board.